This invention relates to a labeling apparatus and more particularly, to a labeling apparatus for the application of labels to fruit and/or vegetables.
Labels are applied to fruit and vegetables in packing houses, where the speed at which the labels are applied and the accuracy of the label application are important considerations. Speed is important because the fruit must be packed and shipped quickly so that the shelf life in stores will be as long as possible and the speed of the labeler may be a limiting constraint. The constraint of labeler speed may also result in inefficient use of other equipment and personnel in the packing house, thus increasing the overall cost of operation. Accuracy, in the form of the successful application of the proper label to the fruit, is important because packing house profitability is adversely affected when a label that would have permitted a higher selling price is not applied to fruit otherwise capable of commanding such a higher price.
One known type of labeler used to label fruit and vegetable includes an extendable bellows for placing the labels (see, e.g., U.S. Pat. No. 4,547,252 and EP 0113256). With this type of labeler, the bellows is moved past a magazine or cassette which dispenses the labels from a carrier strip. The labels are held in position on the end of the bellows by application of a vacuum to the bellows that is pulled through openings in the end of the bellows. The vacuum also serves to maintain the bellows in a retracted position. As the bellows is moved to an application position adjacent a fruit, positive pressure is applied and the bellows is extended to contact the fruit and apply the label thereto.
To prevent a label from blowing off the end of the bellows when the bellows is extended by positive air pressure and thereby missing the fruit, the bellows typically includes some sort of mechanism that prevents air from flowing out of the bellows. One such mechanism is a tricuspid check valve which is integrally formed on the distal end of the bellows. The valve admits air from outside the bellows to the interior of the bellows, but prevents the flow of air out of the bellows. Another such mechanism is a flexible diaphragm that is secured inside the distal end of the bellows. When a vacuum is applied, the diaphragm opens to expose a series of openings in the distal end of the bellows. When positive pressure is applied to extend the bellows, the flexible diaphragm seals against the openings.
Unfortunately, both the integrally formed check valve and the diaphragm arrangement are subject to becoming clogged with dirt and debris. This dirt and debris can prevent the valve or diaphragm from operating properly. For example, if the valve or diaphragm becomes stuck open, when positive pressure is applied, the label may be ejected prematurely. If the valve or diaphragm becomes gummed in a closed position, the bellows may not pick up the labels and the dispensing cassette may jam thereby requiring maintenance. As a result, the bellows must be routinely removed and washed to get rid of the build-up of dirt and debris.
Another type of mechanism used in an expandable bellows labeler to prevent the label from blowing off the end of the bellows is a spiral tube assembly. The spiral tube assembly includes a flexible coil tube that is positioned within the bellows and can be used to provide vacuum at the end of the bellows as the bellows is being expanded. Unlike a check valve or diaphragm arrangement, the spiral tube assembly is not subject to becoming clogged with dirt or debris.
However, the spiral tube assembly has several other shortcomings. For example, the spiral tube assembly consists of four parts which can be difficult to assemble correctly. As a result, the spiral tube assembly requires a relatively labor intensive and time-consuming assembly process. Additionally, because of the arrangement and movement of the parts, the spiral tube assembly has a relatively short life span. The spiral tube assembly is also difficult to service and replace. For example, the bellows must be placed in a certain orientation to allow the operator to see the fitting to which the tube is attached. The spiral tube assembly can limit the distance that the bellows can expand and also resists expansion of the bellows thereby making the bellows less responsive at higher speeds.
A labeler for applying labels to articles is provided. The labeler includes a label application device having an opening in an end thereof. The label application device is expandable when subjected to pressure.
The labeler also includes a positioner for supporting the label application device and moving the label application device between a label pick-up position and a label application position. A vacuum source and a pressure source are also provided which can be selectively connected to the label application device such the label application device is subject to pressure when adjacent the label application position and subject to vacuum for picking up and retaining a label on the label application device at the label pick-up position.
The labeler also includes a flow control element having at least one flow control passage therein which defines at least one air flow path through the flow control element to the label application device opening. The flow control passage is configured to allow air flow through the air flow path and out the label application device opening when pressure is applied to the label application device, but being effective to delay the air flow from reaching the label application device opening to prevent the label from being blown off of the end of the bellows.